A problem common to many types of receptacles is that of providing adequate closure means once the receptacle has been opened, and before the entire content of the receptacle has been consumed. This problem is particularly acute in the case of carbonated beverages where the content of the receptacle will deteriorate if the receptacle is not adequately sealed.
A common receptacle for holding carbonated beverages is a metal can, usually an aluminum can. A number of pull-tab tops have been provided in the past for such cans. A contemporary type can protects the environment by providing a pull-tab or pull-ring that remains attached to the can after the can has been opened. In this type of can a lid tab bends down into the can and also remains attached to the lid after opening. Cans of this type are superior to the prior cans in that no metal member is discarded after the can is opened. Prior to this type of can, a metal tab was discarded after the can was opened, and many times the tab was swallowed by fish or animals, or often the metal tab resulted in injury to the bare foot of an individual.
A common size contemporary can is a ten ounce beverage can having a relatively thin metal top, usually aluminum, to which a tab or ring is pivotally attached. This tab lies flat against the can's lid or top during storage and the like. When the can is to be opened, the tab is manually pivoted upward. This action provides a force against a severable tab portion of the lid. This severable portion of the lid is connected to the remainder of the lid in a sealed manner by way of a score line that is formed in the metal lid. This score line outlines a generally wedge shaped or key-hole shaped opening that will be formed in the lid upon manual operation of the tab. Operation of the manual tab severs this lid or tab portion from the lid, and bends it down into the can, leaving the lid portion connected to the lid by a small section of unsevered metal. The manual tab is then manually returned to its original flat position adjacent the top surface of the lid.
Prior art closure members or stoppers do not succeed in sealing the opening in such a contemporary can in that the prior art stoppers do not adequately seal the opening at the opening location which is adjacent the downwardly folded portion of the lid. A number of prior art closure members will now be described.
The prior art shows the concept of a snap-in unitary resilient member having a grooved peripheral edge and a vertically extending tab. This is shown, for example, in U.S. Pat. No. Re. 27,301. This patent shows a resilient closure plug having a peripheral groove that receives the edge of the opening in a pop-top can. A tab on one end of the plug facilitates manual removal of the resilient plug. U.S. Pat. No. 3,428,212 is also of this general type.
The stopper of the present invention improves upon this type of prior art stopper construction in that the stopper of the present invention is uniquely constructed and arranged to accommodate the residual downwardly projected lid tab that remains after a contemporary can is opened. That is, these prior art devices do not seal properly in a contemporary can where a manual tab and a loosened lid tab remain in place after the can has been opened.
U.S. Pat. No. 3,659,738 is also of interest in that this patent describes a closure device for a can of the type in which a severed lid tab remains attached to the lid after opening. The closure device of this patent comprises a terraced stopper having three triangular sides, two sides having multiple grooves of receding triangular shape, while the third side is smooth and abuts the downwardly projecting lid tab. Again, no attempt is made to control the position of the bent down lid tab. In the present invention, as will be apparent, the stopper is uniquely constructed and arranged to force the lid tab up under the lid, thus providing a known sealing force against the lid tab.
A stopper for sealing a pop-top can that has been opened to expose an essentially wedge or key-hole shaped opening in the top of the can, the stopper substantially matching the shape of the hole and including flanges for engaging the upper and lower surfaces of the can's lid, and the stopper including a handle member for inserting or removing the stopper, is shown in a number of prior patents, such as; U.S. Pat. No. 4,103,804 wherein a wedge shaped resilient stopper having wings and a U-shaped spring internal to the wigs; U.S. Pat. No. 3,664,541 which shows a resilient plug having layers of decreasing dimension to accommodate tab openings of various sizes, and having a handle extending along the plug's longitudinal axis; U.S. Pat. No. 3,650,432 which shows a flexible, pan-like plug having internal ribs arranged in a grid pattern, and having a flat tab on its side to facilitate removal; U.S. Pat. No. 3,622,034 which shows a deformable one piece stopper having overlying legs to engage the top of the can, and a the lower lip that sealingly engages the underside of the can lid; U.S. Pat. No. 3,442,377 which shows resilient stoppers that force fit into a pull tab hole or key-hole shaped opening, etc.; U.S. Pat. No. 3,338,462 which shows a flat plastic member having a stopper at one end and a grippable tab at the other end; U.S. Pat. No. 2,841,307 which shows a deformable stopper having a hollow interior; and U.S. Pat. No. 2,173,843 which shows another deformable stopper.
While the devices of the prior art are generally satisfactory for their intended purposes, the prior art does not address nor solve the problem o sealing a can of the contemporary type, in which, once the can is opened, the stopper must accommodate both a manual operator or tab that remains attached to the top surface of the lid, and a portion of the lid that has been severed therefrom and now extends down into the can, to a position under the lid.
As will be apparent, the beverage can stopper of the present invention is uniquely constructed and arranged to effectively seal such a contemporary can.